Liquid discharging apparatus and wiring member

ABSTRACT

A liquid discharging apparatus includes: liquid discharging modules which are arranged in a first direction along a predetermined plane; and a wiring member commonly joined to the liquid discharging modules. The wiring member includes: first parts joined to the liquid discharging modules, respectively, in a state that the first parts are arranged side by side in the first direction along the predetermined plane; second parts; and a sixth part. The second parts include: third parts extending from the first parts, respectively, in a second direction orthogonal to the first direction and along the predetermined plane, fourth parts extending in a third direction away from the predetermined plane, and fifth parts connected to the third parts and the fourth parts, respectively. Width in the first direction of each of the second parts is smaller than width in the first direction of the sixth part.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation application of U.S. patentapplication Ser. No. 17/030,937, filed on Sep. 24, 2020, which is acontinuation application of U.S. patent application Ser. No. 16/573,382,filed on Sep. 17, 2019, which claims priority from Japanese PatentApplication No. 2018-178870, filed on Sep. 25, 2018, the disclosures ofeach of which are incorporated herein by reference in their entirety.

BACKGROUND Field of the Invention

The present disclosure relates to a liquid discharging apparatus and awiring member.

Description of the Related Art

Conventionally, there is known a liquid discharging apparatus providedwith a plurality of head chips arranged in a first direction; a controlboard controlling discharging (jetting) of an ink by the plurality ofhead chips; and a flexible wiring board (flexible print circuit)electrically connecting the plurality of head chips with the controlboard. In this liquid discharging apparatus, the flexible wiring boardhas a first part extending in a second direction orthogonal to the firstdirection and having a wide width in the first direction, and a secondpart extending in the second direction and having a narrow width in thefirst direction which is smaller than that of the first part. An end ofthe first part is branched into a plurality of second parts each ofwhich is connected to one of the plurality of head chips. On the otherhand, an end, of the second part, which is on the side opposite to thefirst part is connected to a connector of the control board. Namely,since the plurality of head chips are connected to the control board viathe flexible wiring board which is provided commonly with respect to theplurality of head chips, it is possible to reduce the number of theconnector in the control board (see Japanese Patent ApplicationLaid-open No. 2007-196455).

SUMMARY

In a case that, in the liquid discharging apparatus described inJapanese Patent Application Laid-open No. 2007-196455, the flexiblewiring board connects the plurality of head chips with the controlboard, the flexible wiring board is bent at the first part, of whichwidth in the first direction is wide, in a direction away from theplurality of head chips. Specifically, the flexible wiring board is bentat the first part along a bending line extending in the first direction.Due to this configuration, in such a case that the bendability of theflexible wiring board is low and that for example, any external force isapplied to the flexible wiring board when the flexible wiring board is(being) connected to the connector of the control board, there is such afear that each of the second parts of the flexible circuit board and oneof the plurality of head chips might peel off or detached from eachother at a joining part therebetween.

In view of the above-described situation, the present disclosure hasbeen made; an object of the present disclosure is to provide a liquiddischarging apparatus in which the bendability of a flexible wiringboard is satisfactory, and the flexible wiring board and each of thehead modules are less likely to peel off or detached from each other ata joining part therebetween.

According to a first aspect of the present disclosure, there is provideda liquid discharging apparatus including: liquid discharging moduleswhich are arranged in a first direction along a predetermined plane; anda wiring member commonly joined to the liquid discharging modules,wherein the wiring member includes: first parts joined to the liquiddischarging modules, respectively, in a state that the first parts arearranged side by side in the first direction along the predeterminedplane; and second parts including: third parts extending from the firstparts, respectively, in a second direction orthogonal to the firstdirection and along the predetermined plane, fourth parts extending in athird direction away from the predetermined plane, and fifth partsconnected to first ends of the third parts and second ends of the fourthparts, respectively, the first ends being located on a side opposite tothe first parts in the second direction, the second ends being locatedon a side close to the predetermined plane in the third direction; and asixth part commonly connected to third ends of the fourth parts, thethird ends being located on a side far from the predetermined plane inthe third direction; and width in the first direction of each of thesecond parts is smaller than width in the first direction of the sixthpart.

According to a second aspect of the present disclosure, there isprovided a wiring member including: a sixth part which extends in apredetermined direction; second parts each of which extends in thepredetermined direction from an end, of the sixth part, on one side inthe predetermined direction; and an eighth part which extends in anorthogonal direction orthogonal to the predetermined direction and whichconnects ends of the second parts on the one side in the predetermineddirection, with each other, wherein in each of the second parts, widththereof in the orthogonal direction is smaller than length thereof inthe predetermined direction, and the width thereof in the orthogonaldirection is smaller than width in the orthogonal direction of the sixthpart.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view of a printer (ink-jet printer) accordingto a first embodiment of the present disclosure.

FIG. 2 is a block diagram depicting the electrical configuration of theink-jet printer.

FIG. 3 is a view depicting a bottom surface of a head unit attached to aline head.

FIG. 4 is a cross-sectional view of FIG. 3, taken along a line IV-IV inFIG. 3.

FIG. 5 is a view depicting the configuration of a liquid discharginghead in a plan view, in a state that piezoelectric elements are exposedby depicting a wiring board and a driver IC in a broken manner.

FIG. 6 is a circuit block diagram depicting the configuration of acircuit from which a driving signal for driving the piezoelectricelements is outputted to the piezoelectric elements.

FIG. 7 is a wave-form chart of a voltage signal inputted to the wiringboard.

FIG. 8 is a plan view depicting the planar shape of a flexible wiringboard before being bent.

FIG. 9 is a plan view depicting the arrangement of wirings in theflexible wiring board.

FIG. 10 is a view depicting a state that second parts are bent in a casethat the flexible wiring board is mounted on the ink-jet printer.

EMBODIMENT Overall Configuration of Ink-Jet Printer 11

An explanation will be given about the overall configuration of anink-jet printer 11 (hereinafter referred to as “printer 11”) accordingto an embodiment of the present disclosure, with reference to FIG. 1.The printer 11 is an example of a “liquid discharging apparatus” of thepresent disclosure. Note that the embodiment which will be explainedbelow is merely an example of the present disclosure, and the embodimentof the present disclosure can be changed or modified as appropriate, ina range not changing the gist of the present disclosure. FIG. 1 depictsa state that the printer 11 is placed on a horizontal plane. In thefollowing description, a side in front of the sheet surface of FIG. 1 isreferred to as “upper side” of the printer 11, and a side beyond (farside of) the sheet surface of FIG. 1 is referred to as “lower side” ofthe printer 11. Further, a front-rear direction and left-right directiondepicted in FIG. 1 are defined as a conveyance direction and anapparatus width direction, respectively. The horizontal plane is anexample of a “predetermined plane”. The conveyance direction is anexample of a “second direction” and a “predetermined direction” of thepresent disclosure. The apparatus width direction is an example of a“first direction” and an example of an “orthogonal direction” of thepresent disclosure. The following explanation will be given whileappropriately using the directional terms which are the front-rear,left-right and up-down (directions).

As depicted in FIG. 1, the printer 11 is mainly provided with a linehead 13, a platen 14, a conveying mechanism 15, a controller 100, etc.The line head 13 has a plurality of head units 20 which are arrangedalong the apparatus width direction. Note that the line head 13 of thepresent embodiment has six pieces of the head unit 20. The plurality ofhead units 20 have a same configuration. As depicted in FIG. 3, each ofthe head units 20 has a plurality of head modules 23. Each of the headmodules 23 is an example of a “liquid discharging module”. A pluralityof nozzles N are open in the lower surface of each of the head modules23. As depicted in FIG. 3, the plurality of nozzle N are aligned in anozzle-alignment direction which crosses the conveyance direction andthe apparatus width direction. The nozzle-alignment direction is anexample of a “fourth direction” of the present disclosure. The specificof the head unit 20 will be described later on.

The platen 14 is a stand or base on which a recording medium 12 isplaced, and is arranged to face the lower surfaces of the respectivehead modules 23. The conveying mechanism 15 has two conveying rollers 15a, 15 b which are arranged so as to sandwich the platen 14 in theconveyance direction therebetween, and a conveying motor 15 c (see FIG.2). Two conveying rollers 15 a, 15 b are driven while being synchronizedwith each other by the conveying motor 15 c. The conveying mechanism 15conveys the recording medium 12, placed on the platen 14, in theconveyance direction by the two conveying rollers 15 a, 15 b.

The controller 100 includes a CPU (Central Processing Unit) 110, a ROM(Read Only Memory) 120, a RAM (Random Access Memory) 130, an ASIC(Application Specific Integrated Circuit) 140, etc., as depicted in FIG.2. The ROM 120 stores programs executable by the CPU 110, a variety ofkinds of fixed data, etc. The RAM 130 temporality stores data necessaryfor executing the program(s) (such as print data, etc.). The ASIC 140 isconnected to various devices (units, components) or driving parts, etc.,of the printer 11 such as the line head 13, the conveying motor 15 c,etc. Further, the ASIC 140 is connected to an external apparatus 160such as a PC (Personal Computer) via a communication interface 150.

The controller 100 controls the head units 20 of the line head 13, theconveying motor 15 c, etc., based on a printing instruction or commandreceived from the external apparatus 160 to thereby execute a printingprocessing of printing an image, etc., on a recording medium 12. Whileexecuting the printing processing, the controller 100 supplies, to thehead units 20, an electric signal for causing the line head 13 todischarge or jet an ink therefrom. Note that the controller 100 and thehead units 20 are electrically connected to each other by a flexiblewiring board 70 (see FIG. 3) via which the electric signal istransmitted. Note that the flexible wiring board 70 is an exemplarywiring member of the present teaching, and the wiring member of thepresent teaching may include a flexible base material and wirings formedin the base material such as a flexible printed circuit (FPC), a chip onfilm (COF), and the like.

In the above explanation, although the variety of kinds of processingexecuted by the controller 100 is explained as being executed by the CPU110, it is allowable that the CPU 110 execute these processings incooperation with the ASIC 140. Further, it is also allowable that thecontroller 100 is provided with a plurality of pieces of the CPU 110 andthat these CPUs 110 perform the processings in a sharing manner.Furthermore, it is also allowable that the controller 100 is providedwith a plurality of pieces of the ASICs 140 and that these ASICs 140execute the processings in a shared manner. Alternatively, it isallowable that only one piece of the ASIC 140 singly performs theprocessings.

Head Unit 20

As depicted in FIG. 3, each of the head units 20 has an outer shape thatis parallelogram constructed of a pair of opposite sides parallel to theapparatus width direction, and a pair of opposite sides parallel to thenozzle-alignment direction. Each of the head units 20 has six pieces ofthe head module 23 which are arranged side by side to one another alongthe apparatus width direction. Each of the six head modules 23 extendsin the nozzle-alignment direction. Each of the six head modules 23 havea same configuration, and electric signals corresponding to the six headmodules 23, respectively, are transmitted to the six head modules 23,respectively, via one piece of the flexible wiring board 70.

Head Module 23

As depicted in FIG. 3, the plurality of nozzles N via which the ink isdischarged is formed in the bottom surface of each of the head modules23. The plurality of nozzles N form two nozzle rows which are nozzlerows NR1, NR2 which are arranged side by side to each other in anorthogonal direction orthogonal to the nozzle-alignment direction; eachof the nozzle rows are formed along the nozzle-alignment direction. Thetwo nozzle rows NR1, NR2 are formed in such a state that the positionsthereof in the nozzle-alignment direction are shifted from each other.Note that the two nozzle rows NR1, NR2 are formed of a same number ofthe nozzles, and that the plurality of nozzles N are formed with equalintervals (spacing distances) therebetween in each of the nozzle rows.Further, the present embodiment is configured such that two kinds ofinks are discharged from each of the two nozzle rows, namely such thatfour kinds of inks are discharged from the two nozzle rows. For example,the present embodiment is configured such that an yellow ink Y and acyan ink C are discharged from the nozzle row NR1, and a magenta ink Mand a black ink Bk are discharged from the nozzle row NR2.

As depicted in FIG. 4, the head module 23 has a channel unit 30 forminga flow channel (channel) for the ink; a liquid discharging head 40causing the ink to be discharged from the nozzles N; and a module case25. The channel unit 30 and the liquid discharging head 40 are attachedto the module case 25 in a state that the channel unit 30 and the liquiddischarging head 40 are stacked in the up-down direction.

The channel unit 30 is provided with, starting from the lower sidethereof: a nozzle plate 31 formed with the plurality of nozzles N; achannel substrate 32; a pressure chamber substrate 33; and a vibrationplate 41. The nozzle plate 31, the channel substrate 32, the pressurechamber substrate 33 and the vibration plate 41 are fixed to one anotherwhile being staked on top of one another. The channel unit 30 is formedwith: descenders 35 communicating with the nozzles N, respectively;pressure chambers 36 communicating with the descenders 35, respectively;liquid supplying channels 37 communicating with the pressure chambers36, respectively; and a common liquid chamber 38 communicating with theliquid supplying channels 37. Among those as described above, each ofthe descenders 35, each of the pressure chambers 36 and each of theliquid supplying channels 37 are formed to correspond to one of thenozzles N. In contrast, one piece of the head module 23 is formed withfour pieces of the common liquid chamber 38 corresponding to the fourkinds of inks, respectively, and each of the common liquid chambers 38are communicated with nozzles N from which a same kind of the ink isdischarged.

The module case 25 is a member which is substantially box-shaped. Aliquid introducing path 39, configured to introduce an ink from anon-illustrated ink supply source to the common liquid chamber 38 in thechannel unit 30 is formed in the inside of the module case 25. Theliquid introducing path 39, together with the common liquid chamber 38,is a space in which an ink common to a plurality of pieces of thepressure chamber 36 formed to be aligned in the channel unit 30 isstored. In the present embodiment, four pieces of the liquid introducingpath 39 are formed corresponding to the four kinds of the ink,respectively.

The liquid discharging head 40 is provided with, starting from the lowerside thereof: the vibration plate 41 formed with piezoelectric elementsPZ; a wiring circuit board (wiring substrate) 60, and a driver IC 65which outputs a predetermined output voltage. Namely, the wiringsubstrate 60 has a first surface 60 a facing (opposite to) the driver IC65 and a second surface 60 b facing the vibration plate 41.

The vibration plate 41 is a plate-shaped member which is capable ofelastically vibrating. The lower surface of the vibration plate 41constructs the pressure chambers 36 of the channel unit 30, and theupper surface of the vibration plate 41 has the plurality ofpiezoelectric elements PZ which are formed therein and which correspondto the plurality of nozzles N, respectively. Each of the piezoelectricelements PZ has a piezoelectric body 42 which expands and contracts in acase that an electric field acts thereon, and first and secondelectrodes 43 and 44 which are arranged to sandwich, in the up-downdirection, the piezoelectric body 42 therebetween. The first electrode43 is an individual electrode which is formed on the upper surface ofthe piezoelectric body 42, corresponding to each of the pressurechambers 36 (each of the nozzles N). The second electrode 44 is anelectrode which is formed on the upper surface of the vibration plate 41corresponding to the plurality of pressure chambers 36 (plurality ofnozzles N), and which is common to the plurality of piezoelectricelements PZ. In a case that a voltage is applied to the first and secondelectrodes 43 and 44 and that the electric field acts on a certain partor portion, of the piezoelectric body 42, sandwiched by the first andsecond electrodes 43 and 44, the certain part, of the piezoelectric body44, is deformed so as to project toward a certain pressure chamber 36included in the plurality of pressure chambers 36 and corresponding tothe certain part. This causes the vibration plate 41 to be curbed orbent, thereby imparting pressure (pressurizing) the ink inside thecertain pressure chamber 36. In this situation, the ink is dischargedfrom a certain nozzle N included in the plurality of nozzles N andcorresponding to the certain pressure chamber 36. Note that in thiscase, the vibration plate 41 formed with the piezoelectric elements PZis referred to as a piezoelectric-element formation substrate 45.

The first surface 60 a of the wiring substrate 60 is formed with aplurality of first output terminals 91 and a plurality of second outputterminals 92. The plurality of first and second output terminals 91 and92 are electrically connected to the driver IC 65, and an output voltageoutputted from the driver IC 65 is transmitted to the plurality of firstand second output terminals 91 and 92. Namely, an electric circuitconfigured to selectively supply the output voltage with respect to theplurality of piezoelectric elements PZ, etc., are provided or mounted onthe driver IC 65, and bumps 69 a and bumps 69 b are formed on an activesurface, of the driver IC 65, which is a circuit formation surface.Further, the driver IC 65 is electrically connected to the first outputterminals 91 by the bumps 69 a, and is electrically connected to thesecond output terminals 92 by the bumps 69 b. Namely, the driver IC 65is attached to the first surface 60 a of the wiring substrate 60 bymeans of a so-called Flip Chip mounting or packaging.

Furthermore, the wiring substrate 60 is formed with a plurality ofthrough wirings 63 each of which is electrically connected either one ofthe first output terminals 91 and the second putout terminals 92.Moreover, the second surface 60 b of the wiring substrate 60 is formedwith connecting wirings 63 a and connecting wirings 63 b electricallyconnected to the plurality of through wirings 63, respectively. Namely,the first output terminals 91 and the second output terminals 92 formedon a side of the first surface 60 a of the wiring substrate 60 areelectrically connected to the connecting wirings 63 a the connectingwirings 63 b, respectively, which are provided on a side of the secondsurface 60 b of the wiring substrate 60.

Further, the second surface 60 b of the wiring substrate 60 is formedwith first conductive terminals 61 and second conductive terminals 62each of which is electrically connected to the piezoelectric-elementformation substrate 45. In the present embodiment, the first conductiveterminals 61 are each a resin bump which is constructed of an innerresin 64 a and a connecting wiring 63 a formed so as to cover the innerresin 64 a therewith. Further, the second conductive terminals 62 areeach a resin bump which is constructed of an inner resin 64 b and aconnecting wiring 63 b formed so as to cover the inner resin 64 btherewith. Namely, the output voltage outputted from the driver IC 65 istransmitted to the first conductive terminals 61 provided on the side ofthe second surface 60 b of the wiring substrate 60, and is alsotransmitted to the second conductive terminals 62 provided on the sideof the second surface 60 b of the wiring substrate 60. Further, theoutput voltage transmitted to the first conducting terminals 61 issupplied to the first electrodes 43 of the piezoelectric-elementformation substrate 45, and the output voltage transmitted to the secondconducting terminals 62 is supplied to the second electrode 44 of thepiezoelectric-element formation substrate 45, thereby causing the ink tobe discharged from each of the nozzles N.

Further, the first and second conductive terminals 61 and 62 forms, inthe liquid discharging head 40, a gap having a predetermined size(dimension) between the piezoelectric-element formation substrate 45 andthe wiring substrate 60 facing the piezoelectric-element formationsubstrate 45. Namely, the first and second conductive terminals 61 and62, each provided as the plurality of conductive terminals, form the gapbetween the piezoelectric-element formation substrate 45 and the wiringsubstrate 60 such that the vibration plate 41 which deforms in theup-down direction does not make contact with the wiring substrate 60.

Note that after the plurality of first conductive terminals 61 areconnected between the piezoelectric-element formation substrate 45 andthe wiring substrate 60, it is allowable to fill a sealing member 46formed of a resin in a space between the piezoelectric-element formationsubstrate 45 and the wiring substrate 60 and between first conductiveterminals 61 which are adjacent to each other. By doing so, a spacesurrounded by the piezoelectric-element formation substrate 45, thewiring substrate 60, the first conductive terminals 61 and the sealingmember 46 forms a sealed space SC in which the piezoelectric elements PZare sealed (see FIG. 4). In this meaning, the wiring substrate 60 isalso a sealing substrate sealing the piezoelectric elements PZ therein.

Next, an explanation will be given about the configuration of the liquiddischarging head 40, with reference to FIG. 5. Note that thepiezoelectric body 42 is omitted in the illustration of FIG. 5. Asdepicted in FIG. 5, the plurality of first electrodes 43 form, in thepiezoelectric-element formation substrate 45, an electrode row alignedin the nozzle-alignment direction so as to correspond to the nozzles Nin the nozzle row NR1, respectively, and an electrode row aligned in thenozzle-alignment direction so as to correspond to the nozzles N in thenozzle row NR2, respectively.

The first electrodes 43 are formed with projecting electrodes 43 a,respectively, each of which projects toward the outer circumference ofthe piezoelectric-element formation substrate 45. The plurality of firstconductive terminals 61 which are arranged along the nozzle-alignmentdirection are connected with respect to the projecting electrode 43 a,respectively, as depicted as black (solid) circles in FIG. 5. Further,the plurality of second conductive terminals 62 are arranged along thenozzle-alignment direction, and are connected with respect to the secondelectrode 44 of the piezoelectric elements PZ, as depicted as black(solid) circles in FIG. 5.

In the liquid discharging head 40 of the present embodiment, theelectric signal transmitted from the controller 100 via the flexiblewiring board 70 is inputted to the wiring substrate 60. Further, thedriver IC 65 outputs a predetermined output voltage (driving voltage),based on the electric signal inputted to the wiring substrate 60.

Next, an explanation will be given about the electric signal transmittedfrom the controller 100 via the flexible wiring board 70 and the outputvoltage outputted from the driver IC 65, with reference to FIG. 6. Notethat in the present embodiment, in the six head modules 23 aligned inthe head unit 20, the generation of the electric signal transmitted viathe flexible wiring board 70 and the generation of the output voltageoutputted to the piezoelectric elements PZ are performed with a similarcircuit configuration. Accordingly, the explanation will be given aboutone piece among the six head modules 23, as follows.

As depicted in FIG. 6, the controller 100 is provided with a maincontrolling part 52, two voltage-signal generating circuits 53, 54, anda constant-voltage generating circuit 55. Further, an electric circuitconfigured to output a driving voltage VT to the first electrode 43 ofeach of the piezoelectric elements PZ and to output a constant voltageVBS to the second electrode 44 is constructed in the driver IC 65possessed by the liquid discharging head 40.

The main controlling part 52 outputs a variety of kinds of controlsignals, etc., for controlling the voltage-signal generating circuits53, 54 and the electric circuit of the driver IC 65 in a case that animage data as an object (target) of printing is supplied from theexternal apparatus 160 such as the PC, etc. Specifically, the maincontrolling part 52 repeatedly supplies digital data dA to thevoltage-signal generating circuit 53 as one of the voltage-signalgenerating circuits 53, 54; and the main controlling part 52 repeatedlysupplies digital data dB to the voltage-signal generating circuit 54 asthe other of the voltage-signal generating circuits 53, 54. Here, thedata dA defines the signal wave form of a first voltage signal which isan electric signal transmitted to the liquid discharging head 40, andthe data dB defines the signal wave form of a second voltage signalwhich is an electric signal transmitted to the liquid discharging head40.

After the voltage-signal generating circuit 53 as one of thevoltage-signal generating circuits 53, 54 converts the data dArepeatedly supplied thereto into an analogue voltage, the voltage-signalgenerating circuit 53 outputs the first voltage signal, which is ananalogue signal amplified for example by the class D amplification, tothe liquid discharging head 40 as a driving signal COM-A. Similarly,after the voltage-signal generating circuit 54 as the other of thevoltage-signal generating circuits 53, 54 converts the data dBrepeatedly supplied thereto into an analogue voltage, the voltage-signalgenerating circuit 54 supplies the second voltage signal, which is ananalogue signal amplified for example by the class D amplification, tothe liquid discharging head 40 as a driving signal COM-B. Note that thetwo voltage-signal generating circuits 53, 54 have a similar circuitconfiguration except for being mutually different in the data inputtedthereto and in the signal waveform of the voltage signal outputtedtherefrom; a constant voltage VH is used as the power source for thevoltage-signal generating circuits 53, 54.

Further, the main controlling part 52 outputs a control signal Sc forcontrolling the driving of the conveying motor 15 c and controlling theconveyance of the recording medium 12; and the main controlling part 52supplies, synchronizing with the control signal Sc, a variety of kindsof a control signal Ctr to the liquid discharging head 40, as electricsignals. Note that the control signal Ctr supplied to the liquiddischarging head 40 is a digital (binary) voltage signal. In the presentembodiment, the control signal Ctr includes a print data defining an inkamount of the ink to be discharged from the nozzle N, a clock signalused for transmitting the print data, a timing signal defining the printcycle, etc.

Furthermore, in addition to the driving signals COM-A, COM-B and thecontrolling signal Ctr, the constant voltage VBS generated by theconstant-voltage generating circuit 55 is supplied from the controller100 via the flexible wiring board 70. Moreover, a voltage VH which is aconstant potential as a power source for allowing the electric circuitof the driver IC 65 to operate, a voltage VL which is a constantpotential and lower than the voltage VH, and a ground voltage GND (0(zero) V) which is a constant potential and serves as the reference forthe respective voltages, are supplied from the controller 100 via theflexible wiring board 70. In other words, the voltage VH, the voltage VLand the ground voltage GND (0 V) which are the constant potentials,respectively, are supplied via the flexible wiring board 70 each as aconstant-potential signal.

As depicted in FIG. 7, the driving signal COM-A in the presentembodiment has a signal wave form wherein a trapezoidal wave form Adp1which is arranged at a first half period in the print cycle, and atrapezoidal wave form Adp2 which is arranged at a latter half period inthe print cycle are made to be continuous. The trapezoidal wave formAdp1 and the trapezoidal wave form Adp2 have a substantially same waveform; in a case that either one of the trapezoidal wave form Adp1 andthe trapezoidal wave form Adp2 is supplied to the first electrode 43 ofa certain piezoelectric element PZ included in the plurality of thepiezoelectric elements PZ, each of the trapezoidal wave form Adp1 andthe trapezoidal wave form Adp2 indicates a change in the voltage bywhich an intermediate amount of the ink is discharged from a nozzle Nincluded in the plurality of the nozzles N and corresponding to thecertain piezoelectric element PZ.

Further, the driving signal COM-B in the present embodiment has a signalwave form wherein a trapezoidal wave form Bdp1 which is arranged at afirst half period in the print cycle, and a trapezoidal wave form Bdp2which is arranged at a latter half period in the print cycle are made tobe continuous. The trapezoidal wave form Bdp1 and the trapezoidal waveform Bdp2 have mutually different wave forms. Among the trapezoidal waveform Bdp1 and the trapezoidal wave form Bdp2, the trapezoidal wave formBdp1 is a wave form for finely vibrating the ink in the vicinity of thenozzle N to thereby prevent any increase in the viscosity of the ink.Namely, in a case that the trapezoidal wave form Bdp1 is supplied to thefirst electrode 43 of a certain piezoelectric element PZ included in theplurality of the piezoelectric elements PZ, the trapezoidal wave formBdp1 indicates a change in the voltage by which the ink is notdischarged from a nozzle N included in the plurality of the nozzles Nand corresponding to the certain piezoelectric element PZ. Further, in acase that the trapezoidal wave form Bdp2 is supplied to the firstelectrode 43 of a certain piezoelectric element PZ included in theplurality of the piezoelectric elements PZ, the trapezoidal wave formBdp2 indicates a change in the voltage by which a small amount of theink is discharged from a nozzle N included in the plurality of thenozzles N and corresponding to the certain piezoelectric element PZ, thesmall amount of the ink being smaller than the intermediate amount ofthe ink which is discharged in the case of applying the trapezoidal waveform Adp1 or the trapezoidal wave form Adp2 to the first electrode 43.

On the other hand, the other constant voltages which are the voltageVBS, the voltage VH, the voltage VL and the ground voltage GND are eachsuch a constant voltage of which voltage value is not changed (varied)or of which change is slight or small, during the print cycle. Note thatthe constant voltage VBS may be generated, for example as indicated bybroken lines in FIG. 7, such that the voltage value thereof is changedwith one print cycle as an unit period. Further, the voltage VH or thevoltage VL may be generated by the constant-voltage generating circuit55.

Returning to FIG. 6, the driver IC 65 provided on the liquid discharginghead 40 has a selection controlling part 66 and selecting parts 67 whichcorrespond to the plurality of piezoelectric elements PZ, respectively,in one-to-one manner, as an electric circuit configured to supply thevoltage selectively to the plurality of piezoelectric elements PZ.Namely, the driver IC 65 outputs the driving signal COM-A and thedriving signal COM-B, which are transmitted from the controller 100 viathe flexible wiring board 70, selectively to the first electrode 43 of apiezoelectric element PZ among the plurality of piezoelectric elementsPZ.

Specifically, the selection controlling part 66 once stores the clocksignal transmitted from the controller 100 via the flexible wiring board70 and the print data transmitted from the controller 100 via theflexible wiring board 70 while being synchronized with the clock signal,by a number same as the number of the nozzles N (piezoelectric elementsPZ) of the head unit 20. Then, according to the stored print data, theselection controlling part 66 instructs each of the selecting parts 67to perform the selection between the driving signal COM-A and thedriving signal COM-B, at a start timing of the print cycle (first halfperiod, latter half period) which is defined by the timing signaltransmitted from the controller 100 via the flexible wiring board 70.Each of the selecting parts 67 selects either one (or selects none) ofthe driving signals COM-A and COM-B, and outputs the selected one of thedriving signals COM-A and COM-B (or outputs non-selection of either oneof the driving signals COM-A and COM-B) to the first electrode 43 viathe first conductive terminal 61, as the driving voltage VT to beapplied to the piezoelectric element PZ corresponding thereto.

Further, the driver IC 65 outputs a constant voltage to the secondelectrode 44 of each of the piezoelectric elements PZ. Namely, in thepresent embodiment, the constant voltage VBS transmitted from thecontroller 100 via the flexible wiring board 70 is inputted to thedriver IC 65 via the wiring substrate 60. Afterwards, the inputtedconstant voltage VBS is outputted with respect to the second electrode44 common to the plurality of piezoelectric elements PZ of the liquiddischarging head 40, from the driver IC 65 again via the secondconductive terminals 62 provided on the wiring substrate 60.

In the above-described manner, the driving voltage VT is outputted fromthe driver IC 65 selectively to respective one of the plurality ofpiezoelectric elements PZ, thereby applying the driving voltage VTselectively to the first electrodes 43 of the respective piezoelectricelements PZ, and applying the constant voltage VBS to the secondelectrode 44 (which is common to the plurality of piezoelectric elementsPZ). As a result, any expansion and contraction according to thepotential difference (difference in the potentials) between the drivingvoltage VT and the constant voltage VBS is generated in certainpiezoelectric elements PZ which are included in the plurality ofpiezoelectric elements PZ and to which the driving voltage VT isselectively applied, and the ink is discharged from certain nozzles Nwhich are included in the plurality of nozzles N and which correspond tothe certain piezoelectric elements PZ, accompanying with theabove-described expansion and contraction. Then, dots of different sizesare formed on the paper P depending on the amounts of the dischargedink(s). Therefore, the constant voltage VBS may also be considered asone of the driving signals.

Flexible Wiring Board 70

Next, an explanation will be given about the flexible wiring board 70 ofthe present embodiment. Firstly, the planar shape of the flexible wiringboard 70 will be explained, with reference to FIG. 8. In a statedepicted in FIG. 8 before the flexible wiring board 70 is bent, theflexible wiring board 70 has a sixth part 71, six second parts 72branched from the sixth part 71, and an eighth part 73 connecting orlinking the ends of the six second parts 72 with one another. In otherwords, five through holes 77 defined by the sixth part 71, the sixsecond parts 72 and the eighth part 73 are formed in the flexible wiringboard 70.

The sixth part 71 is constructed of a wide-width part 71 a, a taperedpart 71 b and a narrow-width part 71 c. Width W1 in the apparatus widthdirection of the wide-width part 71 a is greater than width W2 in theapparatus width direction of the narrow-width part 71 c. Further, thewidth in the apparatus width direction of the tapered part 71 b is madeto be progressively smaller (tapered) from the wide-width part 71 atoward the narrow-width part 71 c. An input terminal 74 connectable to aconnector of the controller 100 is arranged at the narrow-width part 71c.

The six second parts 72 correspond to the six head modules 23,respectively, and extend in the conveyance direction. Width W3 in theapparatus width direction of each of the second parts 72 is smaller thanthe width W1 of the wide-width part, and is smaller than the width W2 ofthe narrow-width part. Namely, the width W3 in the apparatus widthdirection of each of the second parts 72 is smaller than the width inthe apparatus width direction of the sixth part 71. Each of the secondparts 72 is constructed of a first part 72 a on a side of the eighthpart 73 relative to a bending line F indicated in broken lines in FIG.8, and a second part 72 b on a side of the sixth part 71 relative to thebending line F. Note that a virtual boundary of each of the first part72 a with respect to the eighth part 73 extends in an orthogonaldirection orthogonal to the nozzle-alignment direction. Accordingly,each of the third parts 72 a has a trapezoidal shape of which side onthe right side in the apparatus width direction is a short side, and ofwhich side on the left side in the apparatus width direction is a longside. In the following explanation, the length of the short side of thefirst part 72 having the trapezoidal shape is defined as a “length L1 inthe conveyance direction of the first part 72 a”. Further, a sum of thelength L1 in the conveyance direction of the first part 72 a and lengthL2 in the conveyance direction of the second part 72 b is defined as“length L in the conveyance direction of the branched part 72”. In eachof the second parts 72 of the present embodiment, the width W3 in theapparatus width direction is smaller than the length L in the conveyancedirection.

The eighth part 73 is constructed of first parts 73 a which are providedon six locations arranged side by side to one another in the apparatuswidth direction, and seventh parts 73 b which are provided on fivelocations arranged side by side to one another in the apparatus widthdirection. Each of the first parts 73 a is rectangular-shaped, andextends in the nozzle-alignment direction. One end in thenozzle-alignment direction of each of the first parts 73 a is continuedto the first part 72 a of one of the second parts 72 correspondingthereto. On the other hand, the other end in the nozzle-alignmentdirection of each of the first parts 73 a is provided with a joint area75. The joint area 75 is an area which is joined to the wiring substrate60 of the head module 23, and at which an output terminal (to be)jointed to a contact point of the wiring substrate 60 is arranged. Eachof the seventh parts 73 b is continued to two first parts 73 a includedin the six first parts 73 a and arranged at two locations which areadjacent in the apparatus width direction. In other words, the two firstparts 73 a arranged at the two locations which are adjacent in theapparatus width direction are linked by each of the seventh parts 73 b.The eighth part 73 extending in the apparatus width direction is formedof the first parts 73 a provided on the six locations and the seventhparts 73 b provided on the five locations.

Next, the arrangement of wirings in the flexible wiring board 70 will beexplained with reference to FIG. 9. Firstly, a COM-A wiring 76 aconfigured to transmit the driving signal COM-A therethrough is arrangedfrom the input terminal 74 along the outer shape of the flexible wiringboard 70. The COM-A wiring 76 a is an example of a “driving-signalwiring” of the present disclosure. Further, similarly to the COM-Awiring 76 a, a COM-B wiring 76 b configured to transmit the drivingsignal COM-B therethrough is arranged from the input terminal 74 alongthe outer shape of the flexible wiring board 70. The COM-B wiring 76 bis also an example of the “driving-signal wiring” of the presentdisclosure. The COM-B wiring 76 b is arranged on the inside of the COM-Awiring 76 a. Note that each of the COM-A wiring 76 a and the COM-Bwiring 76 b is cut or broken at a central portion in the apparatus widthdirection of the eighth part 73. With this, a signal from the left sideor a signal from the right side is allowed to be inputted into one pieceof the joining part 73 a, and it is possible to prevent signals fromboth of the left and right sides from being inputted into one piece ofthe joining part 73 a.

A GND wiring 76 c is arranged in an annular shape further on the insideof the COM-B wiring 76 b, so as to conform to the outer shape of theflexible wiring circuit 70 and the outer shape of the five through holes77. Namely, the GND wiring 76 c is provided commonly with respect to thesix head modules 23. Six V-high wirings 76 d, which are drawn from theinput terminal 74 respectively toward the first parts 73 a arranged atthe six locations, are arranged in the inside of an area surrounded bythe GND wiring 76 c. The constant-potential signal is transmitted toeach of the V-high wirings 76 d. Note that the GND wiring 76 c is drawnfrom a central portion in the apparatus width direction of each of thefirst parts 73 a up to the input terminal 74, such that the GND wiring76 c is along the V-high wiring 76 d drawn from each of the first parts73 a. Further, control wirings 76 e which are drawn from the inputterminal 74 toward the first parts 73 a, respectively, and which arearranged at the six locations, etc., are arranged in the inside of thearea surrounded by the GND wiring 76 c. The control signal 76 e istransmitted to each of the control wirings 76 e.

By arranging the respective wirings (the variety of kinds of wirings) asdepicted in FIG. 9, the GND wiring 76 c is arranged along the V-highwirings 76 a on one side or on the both sides relative to each of theV-high wirings 76 d. With this, it is possible to lower a noise due tothe electric current flowing through the V-high wirings 76 d andreaching the COM-A signal 76 a and/or the COM-B signal 76 b, etc.

Note that the flexible wiring board 70 of the present embodiment ismounted on the printer 11 in a state that the flexible wiring board 70is bent upward at the second parts 72, as depicted in FIG. 10. In thisstate, the first part 72 a of each of the second parts 72 extends in theconveyance direction along a horizontal plane, and the second part 72 bof each of the second parts 72 extends in an up direction (upward) suchthat the second part 72 b is away from the head module 23. The up-downdirection is an example of a “third direction” of the presentdisclosure. Further, in FIG. 8, parts, of the respective second parts72, overlapping with the bending line F each correspond to a bendingpart 72 c depicted in FIG. 10. In other words, each of the fifth parts72 c is connected or linked to the end in the conveyance direction, ofone of third parts 72 a corresponding thereto, on the side opposite tothe joining part 73 a, and is connected or linked to the end on thelower side (lower end) of one of the fourth parts 72 b correspondingthereto. The end in the conveyance direction, of each of the third parts72 a, on the side opposite to the joining part 73 a is an example of a“first end” of the present disclosure. The lower end of each of thefourth parts 72 b is an example of a “second end” of the presentdisclosure. Further, the end on the upper side (upper end) of each ofthe fourth parts 72 b is an example of a “third end” of the presentdisclosure.

According to the printer 11 of the present embodiment as explainedabove, one piece of the flexible wiring board 70 is connected to onepiece of the head unit 20. Further, one piece of the head unit 20includes six pieces of the head module 23. Namely, a common flexiblewiring board 70 is connected to the six head modules 23. Accordingly, itis possible to reduce the number of the flexible wiring board, ascompared with a case of connecting the flexible wiring board for each ofthe head modules, thereby making is possible to reduce the number of theconnectors of the controller, as a result.

Further, in the printer 11 of the present embodiment, the flexiblewiring board 70 has the sixth part 71, the plurality of second parts 72and the eighth part 73. The width in the apparatus width direction ofeach of the second parts 72 is smaller than the width in the apparatuswidth direction of the sixth part 71. Further, the flexible wiring board70 is mounted on the printer 11 in a state that the flexible wiringboard 70 is bent in the up direction at each of the second parts 72.Owing to this configuration, the flexible wiring board 70 has asatisfactory bendability; even in such a case that any external forceacts on the flexible wiring board while the flexible wiring board is(being) mounted on the printer 11, the flexible wiring board 70 and theplurality of head modules 23 are less likely to peel off or detachedfrom each other at the joining part therebetween.

Further, in the printer 11 of the present embodiment, the flexiblewiring board 70 is connected to the ends, of the respective head modules23, in the nozzle-alignment direction. Owing to this configuration, thewidth in the orthogonal direction orthogonal to the nozzle-alignmentdirection of each of the head modules 23 can be made small, as comparedwith a case of connecting the flexible wiring board between two nozzlerows in each of the head modules 23.

Furthermore, in the printer 11 of the present embodiment, the fivethrough holes 77 are formed in the flexible wiring board 70. Owing tothis configuration, it is possible to easily position the flexiblewiring board 70 with respect to the six head modules 23 while theflexible wiring board 70 is being jointed to the six head modules 23.

Moreover, in the printer 11 of the present embodiment, the eighth part73 continued from the six second parts 72 is provided on the flexiblewiring board 70. Further, the COM-A wiring 76 a and the COM-B wiring 76b are arranged on the eighth part 73 commonly with respect to theplurality of head modules 23. Owing to this configuration, it ispossible to reduce the number of the wirings, as compared with a case ofproviding these wirings with respect to each of the head modules 23.

Note that in the present embodiment, it is allowable that the widths ofthe COM-A wiring 76 a and the COM-B wiring 76 b arranged in the flexiblewiring board 70 are not uniform. Namely, the widths of these wirings 76a and 76 b may be adjusted such that the impedances in routes arrivingat the six head modules 23 (driver ICs 65) are substantially same. Forexample, each of the COM-A wiring 76 a and the COM-B wiring 76 b mayhave such a width which becomes greater from the outer side toward thecentral side in the apparatus width direction, at the eighth part 73 ofthe flexible wiring board 70. In a case that these wirings 76 a and 76 bare arranged along the outer shape of the flexible wiring board 70 andare cut at the central portion in the apparatus width direction as inthe present embodiment, a distance up to a head module 23, among the sixhead modules 23, which is joined to the flexible wiring board 70 on thecentral side in the apparatus width direction is longer than a distanceup to another head module 23, among the six head modules 23, which isjoined to the flexible wiring board 70 at the outer side in theapparatus width direction. Accordingly, by making the width of each ofthe wirings 76 a and 76 b to be greater from the outer side toward thecentral side in the apparatus width direction, it is possible to madethe difference in impedance among the routes to be small. Further, inview of further making the difference in impedance among the routes tobe smaller, it is allowable that the plurality of head modules 23 havethe connecting terminals which are to be connected with respect to theflexible wiring board 70 and which are disposed at mutually differentpositions among the plurality of head modules 23. For example, it isallowable that the connection terminal of a head module 23, among theplurality of head modules 23, which is located at the central side inthe apparatus width direction, is arranged such that the distance fromthe connecting terminal up to the driver IC 65 is shorter than that inanother head module 23, among the plurality of head modules 23, which isarranged at the outer side in the apparatus width direction.

The above-described embodiment applies the present disclosure to anink-jet head which discharges or jets an ink onto a recording papersheet so as to print an image, etc., on the recording paper sheet.However, the present disclosure is applicable also to a liquiddischarging apparatus usable in a variety of kinds of usage orapplication other than printing of image, etc. For example, it is alsopossible to apply the present disclosure to a liquid dischargingapparatus configured to form a conductive pattern on a surface of asubstrate by discharging or jetting a conductive liquid onto thesubstrate.

What is claimed is:
 1. A liquid discharging apparatus comprising: headunits arranged in a first direction along a predetermined plane; andflexible wiring boards drawn from the head units respectively toward asecond direction orthogonal to the first direction and along thepredetermined plane, wherein each of the head units includes nozzles,elements configured to cause liquid to be discharged from the nozzles,and an IC configured to selectively supply an output voltage to theelements, the nozzles are aligned in a nozzle alignment direction thatis along the predetermined plane and intersects with both the firstdirection and the second direction, each of the head units has an outershape that is a parallelogram and that is not a rectangle, wherein eachparallelogram comprises a pair of opposite sides parallel to the nozzlealignment direction; each of the flexible wiring boards is joined toonly one side of corresponding one of the head units, in a state ofbeing bent toward a third direction away from the predetermined plane,and each of the flexible wiring boards is not joined to the other sidesof the corresponding one of the head units.
 2. The liquid dischargingapparatus according to claim 1, wherein each of the flexible wiringboards includes a driving signal wiring through which a driving signalis supplied to the corresponding one of the head units.
 3. The liquiddischarging apparatus according to claim 1, wherein each of the flexiblewiring boards includes a constant potential wiring through which aconstant-potential signal is supplied to the corresponding one of thehead units.
 4. The liquid discharging apparatus according to claim 1,wherein each of the flexible wiring boards includes a control wiringthrough which a control signal is supplied to the corresponding one ofthe head units.